1. Field of the Invention
The present invention relates to a chair.
2. Description of the Background Art
A type of chairs such as office chairs has been proposed, of which the chair seat is moveable in linkage with the movement of the occupant to recline against the backrest. Specific examples are proposed in U.S. Pat. No. 6,149,236 to Brauning and Japanese patent laid-open publication No. 37438/1992. Another specific example can be found on the website of Wilkhahn, “Modus: Function” [[ ]], Internet Watch, retrieved on Jun. 15, 2006.
A conventional chair will briefly be described. An example of conventional chair has a base that comprises a support stem or stems and caster wheels, and is to be settled on the floor surface. The base is formed so as to bear the weight of the entire chair and the occupant who would be seated thereon. On top end of the base, a chair seat is swivelably mounted on which the occupant is to be seated. The base has its intermediate portion provided with an articulation to which a first link is pivotally connected at its one end so as to support the occupant, when seated thereon.
The first link is formed to bend at a predetermined angle to support the chair seat and the chair back. The chair back has a backrest attached to the first link. The first link and the chair seat are connected to each other by a second link, which has its opposite ends linked with respective articulations to swivelably support the chair seat with respect to the first link.
When the occupant is seated on the chair and reclines against the chair back, the first link that supports the chair back swivels about the articulation with respect to the base. The chair seat is connected to the first link by the second link, and therefore swivels about the articulation relative to the base simultaneously with the first link. That is, the mechanism is constituted such that the chair seat can be inclined rearward by an amount associated with the rearward inclination of the chair back.
With the conventional chair, however, since the chair seat is inclined rearward by an amount associated with the amount by which the chair back is inclined rearward, the angle between the chair seat and the chair back does not increase beyond the amount by which the chair back is inclined rearward, thus making it impossible for the occupant to keep his or her optimum seating posture. More specifically, when the occupant sits on the chair seat and wants to take a relaxed reclined position, comfort of the occupant may be compromised in some cases due to the lack of the angle between the chair seat and the chair back.
In order to mitigate such an inconvenience, the occupant often sits with the rear of the body shifted toward the front of the chair seat in the reclined posture, and extends his or her hip joint. However, this posture may be against the social behavior of deeply sitting on the chair seat for proper seating posture. For this reason, the sitters tend to impose the increased stress on his or her buttocks and other parts of the body.